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#11597540 - 05/11/16 05:27 PM Prop question
Bobby Milam Offline
Extreme Angler

Registered: 07/13/14
Posts: 2014
Loc: Arlington
I purchased a 1994 Champion 17'6" a couple of weeks ago. It is on a '94 Mercury 115 hp motor. The manual says the maximum RPM is 4700-5250. If my tach is correct, I am planning on verifying that it is, I hit the max rpm between half and 3/4 wot. I have to really keep an eye on the tach to keep from over revving the motor. It has a terrific hole shot, getting on plane almost instantly but lacks top end. Looks like it's about 40 (GPS) when I have to ease off the throttle. The prop that is on it right now is a kc quick silver 48 16988 a5 18p. I do have another prop in the boat which is larger but there are no markings on it that I can find. I assume that it is the original prop but it has a few nicks on the blades.

I am thinking about switching the props out and see what it does. Since I don't know anything about props size and pitch I thought that I'd ask in here about it. I really would like to get a prop that matched the motor better so I don't have to worry about over revving

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#11597572 - 05/11/16 05:44 PM Re: Prop question [Re: Bobby Milam]
bronco71 Offline
Extreme Angler

Registered: 02/05/06
Posts: 1049
Loc: Farmers Branch/Sulphur Bluff
I would try to borrow a 21p stainless steel, maybe even a 22p Laser II, and try it, should be better than the 18p. Also check height of motor on transom, might be able to raise motor some using existing transom holes or better yet add a jackplate...shoot for 3 to 3.5" propshaft below the hull while still picking up water for the pump.

As a rule every 2" lncrease in pitch decreases your WOT by about 200 RPMs.

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#11597619 - 05/11/16 06:14 PM Re: Prop question [Re: Bobby Milam]
Bobby Milam Offline
Extreme Angler

Registered: 07/13/14
Posts: 2014
Loc: Arlington
Thanks for the advise. I don't know anyone to borrow one from. I know there are some prop shops around Fork. Anyone know if they have testers to select the right one before you buy? Seems like I remember seeing something about that before. Closer to Arlington is even better.


Edited by Bobby Milam (05/11/16 06:14 PM)

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#11597645 - 05/11/16 06:31 PM Re: Prop question [Re: Bobby Milam]
bronco71 Offline
Extreme Angler

Registered: 02/05/06
Posts: 1049
Loc: Farmers Branch/Sulphur Bluff
James propeller is in Farmers Branch and McGills propeller is in Lewisville but I don't know if they have loaners....they can definately tell you what you need and work it to get it right. They might even give you something for trade in, but you may want to keep yours as a spare or as a power prop if you ever pull a couple skiers.

I have a 23p Mercury Vengeance for sale but I am pretty sure it is too large in diameter for your motor. I believe yours uses about a 13" diameter and mine is around 14 - 14.5" off of a 150hp....



Edited by bronco71 (05/11/16 06:34 PM)

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#11598646 - 05/12/16 07:53 AM Re: Prop question [Re: Bobby Milam]
2015fordnut Online   sick
Extreme Angler

Registered: 06/24/09
Posts: 1705
Loc: Garland, TX
Find the real answers to your questions as well as sound professional advice. Call Josh and or talk to Steve. You prolly need a 6" jackplate and a 21 pitch prop but don't take my word as gospel call these guys. http://www.stevescustomprops.com


Edited by 2015fordnut (05/12/16 07:55 AM)
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#11599758 - 05/12/16 03:12 PM Re: Prop question [Re: Bobby Milam]
Pat Goff Offline
TFF Team Angler

Registered: 01/29/05
Posts: 4996
Loc: Marble Falls/Seadrift
Rapid jack 6" with the champ offset.
Raker 24 WORKED or 24 tempest with OMC hub kit.

3 3/4" shaft under pad will be really close to potential.
A raker out of the box is a turd, it's got to get worked by a SKILLED hand. Not some moron with a hammer and anvil.
_________________________
Pat Goff
Marble Falls/Seadrift TX

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#11599821 - 05/12/16 03:43 PM Re: Prop question [Re: Bobby Milam]
Bobby Milam Offline
Extreme Angler

Registered: 07/13/14
Posts: 2014
Loc: Arlington
I measured and it's right around 3 3/4" right now. Going to put the other prop that was in the boat on and see what it does. Also will call the prop shop and see what they can do. I don't care about speed, just want this to be right


Edited by Bobby Milam (05/12/16 03:45 PM)

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#11600087 - 05/12/16 07:08 PM Re: Prop question [Re: Pat Goff]
militarybrat Offline
Extreme Angler

Registered: 06/02/11
Posts: 2600
Loc: dalllas texas
Originally Posted By: Pat Goff
Rapid jack 6" with the champ offset.
Raker 24 WORKED or 24 tempest with OMC hub kit.

3 3/4" shaft under pad will be really close to potential.
A raker out of the box is a turd, it's got to get worked by a SKILLED hand. Not some moron with a hammer and anvil.

You do this^^^^^ and that boat will run its best most efficient. Mr. Goff has a year or 2 in champions.
_________________________
Who ever said nothing in life is impossible.
Never tried slamming a revolving door.

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#11600708 - 05/13/16 07:35 AM Re: Prop question [Re: Bobby Milam]
steve@scp Offline
TFF Celebrity

Registered: 08/25/06
Posts: 6629
Loc: Quitman,Tx
Pat is mostly correct.

except the raker or tempest won't fit that 115hp engine.

6" plate i have in stock for you.

a 22p laser II with some cup work done and you'll be flying down the lake again.


Edited by steve@scp (05/13/16 07:36 AM)
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#11601455 - 05/13/16 01:54 PM Re: Prop question [Re: Bobby Milam]
Pat Goff Offline
TFF Team Angler

Registered: 01/29/05
Posts: 4996
Loc: Marble Falls/Seadrift
Older I get the more blind. Steve is right I thou ltd I read 150
_________________________
Pat Goff
Marble Falls/Seadrift TX

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#11601482 - 05/13/16 02:08 PM Re: Prop question [Re: Bobby Milam]
Bobby Milam Offline
Extreme Angler

Registered: 07/13/14
Posts: 2014
Loc: Arlington
I'm having to put the prop on the back burner right now because I am having some motor issues. Idles fine but has no power to get on plane now after I hit a huge wave. Got to get it into a mechanic and see what happened.

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#11602841 - 05/14/16 01:05 PM Re: Prop question [Re: Bobby Milam]
txmasterpo Offline
TFF Team Angler

Registered: 11/10/12
Posts: 4489
Loc: Emory
It's certainly way under propped now....Steve did a laser II for me and I love it.....I run more pitch though...
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"What goes on around you compares little with what goes on inside you."

Ralph Waldo Emerson

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#11738111 - 07/23/16 01:03 PM Re: Prop question [Re: Bobby Milam]
Bobby Milam Offline
Extreme Angler

Registered: 07/13/14
Posts: 2014
Loc: Arlington
Been using the 18p prop until I could get a new one. Came across a laser 2, 22p prop at a good price so I bought it. This is the marking on the prop, quicksilver 48 16992 a40 22p. Same 13/5" and 22P. Everything that I read shows that this should be roughly 800 RPM less than the 18P. I put it on last night and gave it a try. My first observation was when running at idle, the old prop wouldn't run less than about 3.5 MPH, at 4000 RPM it runs roughly 30 MPH. The new prop was running 2.8 MPH. At the same rpm of 4000, it only ran 28MPH with no wind or wave. Throttle position is still about the same 3/4 position. The new prop is harder to get on plane with, which I had expected. It seems like it changed nothing but the bottom end.

Now I am totally confused. I didn't expect it to be a perfect setup with no jackplate or cupping done but why is my throttle and RPMs about the same if not worse on the new prop?

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#11738330 - 07/23/16 04:03 PM Re: Prop question [Re: Bobby Milam]
bronco71 Offline
Extreme Angler

Registered: 02/05/06
Posts: 1049
Loc: Farmers Branch/Sulphur Bluff
It is better to prop it to hit your max rpm at WOT and then adjust from there. It does seem strange that it is slower at the same 4000 rpm but that could be a lot of things....blade size, amount of boat in water, slip etc. Different prop configurations lift the boat differently at different speeds.

I try to setup my prop to be very close to max rpm at WOT and to break loose when punching from dead stop revving to around 3500 rpm then hooking up and on plane in about 3-4 seconds. Blade size and number of blades determine handling of boat cruising and WOT... and bow lift.


Edited by bronco71 (07/23/16 04:05 PM)

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#11738334 - 07/23/16 04:06 PM Re: Prop question [Re: bronco71]
smooth move Offline
Pro Angler

Registered: 10/14/12
Posts: 884
Loc: bayou vista,tx
Originally Posted By: bronco71
It is better to prop it to hit your max rpm at WOT and then adjust from there. It does seem strange that it is slower at the same 4000 rpm but that could be a lot of things....blade size, amount of boat in water, slip etc. Different prop configurations lift the boat differently at different speeds.

I try to setup my prop to be very close to max rpm at WOT and to break loose when punching from dead stop revving to around 3500 rpm then hooking up and on plane in about 3-4 seconds. Blade size and number of blades determine handling of boat cruising and WOT... and bow lift.

very well put. thanks.
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